FIG. 10.

Role of I_NaP in the generation of the one-phase oscillations. A: output activity of early-I neuron at the values of g¯_NaP = 5.0 nS (top trace), g¯_NaP = 3.0 nS (middle trace), and g¯_NaP = 2.5 nS (bottom trace). B: relative changes in the oscillation period (solid line) and the amplitude (dashed line) with g¯_NaP variation from 0 to 5 nS; note that oscillations were abolished near g¯_NaP = 2.6 nS. C: bifurcation diagram for equation systems 1, 2, and 5 with parameter g¯_NaP. For each g¯_NaP, the system has a unique equilibrium point, whereas for sufficiently large g¯_NaP, the system exhibits one-phase oscillations. Labeling conventions are as in Fig. 9. Oscillations are terminated in an AH bifurcation near g¯_NaP = 2.6 nS. D: nullclines and one-phase oscillations in the (V₁, h_NaP) plane for g¯_NaP values as indicated. Because g¯_NaP = 2.6 nS is so close to the AH bifurcation, the oscillation at this value is not apparent on this scale.